Electronic engine controls are known in the prior art. Such engine controls typically input signals from one or more engine parameter sensors and output an injection signal or fuel delivery signal that causes fuel to be introduced into the engine cylinders in accordance with a predetermined fuel delivery schedule.
Engine fans are typically driven by the engine through a series of belts and pulleys or other means. The rotating cooling fan draws air through a radiator, which transfers heat from the engine coolant in the radiator to the air, thereby extracting heat from, and reducing the temperature of, the engine coolant. In this manner, the engine fan helps keep the engine within normal operating temperatures.
In engines equipped with a turbocharger, the fan is often used to draw air through an air-to-air aftercooler. The fan draws air through the aftercooler thereby reducing the temperature of the compressed air as it exits the turbocharger and before it enters the intake manifold. In this manner, the air entering the intake manifold can be maintained within normal operating temperatures.
The power required to operate the cooling fan is sometimes referred to as parasitic power because that power does not contribute to the work output of the engine. To improve the overall efficiency of the engine, it would therefore be desirable to decrease the parasitic power required to operate the cooling fan, or to eliminate entirely the power required by the fan in those instances where the fan is not required to keep the engine within a range of normal operating temperatures.
The present invention is directed to overcoming this and other problems associated with electronic engine controls.